The invention relates generally to an electronic transceiver assembly, and more particularly, to a receptacle which is mounted on a circuit board and a transceiver module pluggable into the receptacle.
Various types of fiber optic and copper based transceivers that permit communication between electronic host equipment and external devices are known. These transceivers may be incorporated into modules that can be pluggably connected to the host equipment to provide flexibility in system configuration. The modules are constructed according to various standards for size and compatibility, one standard being the Small Form-factor Pluggable (SFP) module standard.
The SFP module is plugged into a receptacle that is mounted on a circuit board within the host equipment. The receptacle includes an elongated guide frame, or cage, having a front that is open to an interior space, and an electrical connector disposed at a rear of the cage within the interior space. Both the connector and the guide frame are electrically and mechanically connected to the circuit board, and when an SFP module is plugged into a receptacle it is electrically and mechanically connected to the circuit board as well. Conventional SFP modules and receptacles perform satisfactorily carrying data signals at rates up to 2.5 gigabits per second (Gbps).
A standard currently in development for a next generation of SFP modules, presently being called the XFP standard, calls for the transceiver modules to carry data signals at rates up to 10 Gbps. The transceiver modules will encounter several problems at the increased data rate not experienced previously. One problem is that the transceiver modules and the surrounding circuitry will generate significantly greater quantities of heat to be removed in order for the electronic components to survive long term. Another problem is that the transceiver modules will generate increased quantities of electromagnetic (EM) energy at very short wavelengths. As the EM energy at the short wavelengths increases, the potential exists for more EM energy to pass through gaps in the shielding of the receptacle or guide frame. As more EM energy is accepted through the receptacle, the data signals conveyed by adjacent transceiver modules experience more EM interference (EMI). It is desirable to shield or isolate the data signals from EMI to the extent practical.
Further, conventional transceiver module assemblies include latch mechanisms to secure the transceiver module in the receptacle and to eject the transceiver module from the receptacle. It is desirable to provide a latch mechanism that is reliable, secure and robust.
There is a need to improve the design of a pluggable electronic module and receptacle in order to overcome present deficiencies and anticipated problems, among other things, due to higher data rates.
In accordance with an exemplary embodiment of the invention, a receptacle assembly is provided. The assembly comprises a guide frame having a front end with an opening to an interior cavity of the guide frame. The opening is configured to receive a module assembly. The guide frame has a bottom with a bottom opening to the interior cavity, and the bottom is configured to be joined to a circuit board. An EMI gasket is provided along at least a portion of a perimeter of the bottom opening to be held between the guide frame and a circuit board. The EMI gasket forms a shielded interface along the portion of the perimeter of the bottom opening.
In an exemplary embodiment, the EMI gasket includes a series of conductive straps provided along a leading edge of the bottom opening nearest the front end. The conductive straps are provided along the leading edge and have widths sufficient to cover a substantial majority of the leading edge to form a shielded interface along the leading edge. An EMI gasket including a skirt extending partially along a portion of the perimeter of the bottom opening is also provided, and the skirt is formed of a rubber elastomer containing conductive particulate material.
In accordance with another exemplary embodiment of the invention, a transceiver receptacle assembly is provided. A guide frame has a front end with an opening to an interior cavity of the guide frame, and the opening is configured to receive a transceiver module assembly. The guide frame has a bottom with a bottom opening to the interior cavity, and the bottom is configured to be mounted to a conductive layer provided on a circuit board. The bottom opening is configured to receive a receptacle connector mounted to the printed circuit board. An EMI gasket is provided along at least a portion of an edge of the bottom opening, and the EMI gasket is compressible between the guide frame and the conductive layer on the circuit board.
The EMI gasket includes conductive straps provided along one edge of the bottom opening, and conductive straps are deflectable by the transceiver module assembly to directly engage the conductive layer of the circuit board. Separate gaskets are provided on the remaining edges of the bottom opening. The guide frame is mounted to the circuit board with the receptacle connector extending upward into the bottom opening, and the EMI gaskets surround the receptacle connector.